Our over-all objective is to elucidate the nature of viral gene regulation and function in polyoma and SV40 infection. Our goals for the coming year are to isolate and characterize proteins associated with replicative intermediates of polyoma and SV40 DNA. An attempt will be made to determine which, if any, of these proteins are virus-specific and which are host proteins. The synthesis and stability of these proteins will be analyzed in relation to other events occurring during the course of infection, such as synthesis of messenger RNA, induction of DNA and histone synthesis and formation of capsid proteins. Proteins and DNA- protein complexes will be examined for the possession of enzymatic activity, especially with regard to DNA and RNA synthesis. We will also attempt to determine at what sites these proteins are located on replicating and mature DNA molecules and whether they function as repressor molecules or perhaps directly as maturation proteins.